1. Field of the Invention
The present invention relates to a solid-state image sensor and an image capturing apparatus.
2. Description of the Related Art
Recently, downsized image capturing equipment including special effects and functions with a simple configuration have been available. Image-capturing equipment capable of readily acquiring parallax information to serve as the basis of the three-dimensional image of an object space can be given as an example. Also, in order to quickly and accurately perform focus adjustment of the imaging optical system of image capturing equipment, more accurate detection of the object distance based on parallax information for acquiring three-dimensional information is desired.
As such a technique for quickly and accurately performing focus detection, Japanese Patent Laid-Open No. 60-125814 discloses a configuration in which a focus detection means employing the phase-difference detection method is combined with a focus detection mechanism. Also, as an example of the configuration that does not employ a dedicate unit for focus detection, Japanese Patent Laid-Open No. 2007-158109 discloses a technique in which a portion of image sensing pixels of the solid-state image sensor are used as focus detecting pixels in the phase-difference system.
However, the technique disclosed in Japanese Patent Laid-Open No. 60-125814 requires a dedicated unit for focus detection, and when performing focus detection, the whole or part of light incident on the solid-state image sensor needs to be received. Also, the technique of Japanese Patent Laid-Open No. 2007-158109 employs a complex electrical configuration in order to differentiate a portion of the array of a solid-state image sensor, and the image sensing pixels are used as the focus detecting pixels without changing the configuration thereof. Thus, accurate focus detection cannot be performed.